The Meriwether Society database shows that Elizabeth Hubard, wife of John Bowyer, was the great-granddaughter of Mary Meriwether (ca 1686-6 Oct 1750) and her first husband, William Colston. Mary was the daughter of Francis Meriwether and Mary Bathurst. Francis was the son of the immigrant, Nicholas Meriwether (1631-1678).
So, yes, Louise would be the third cousin twice removed of Capt. Meriwether Lewis, who never married and had no known descendants.
The TMSI database did not have Louise as a daughter of John and Elizabeth, but they did have a son named John Colston Bowyer. So it looks like John & Elizabeth went back to Elizabeth's great grandparents for middle names of at least two children. And I wonder if her husband R. E. Colston was a Colston cousin?
I would love to exchange info with any researchers who have information on descendants of John and Elizabeth.
The Meriwether Societydata@MeriwetherSociety.org